In the field of the magnetic disc, a floppy disc drive using a 2 MB MF-2HD floppy disc using Co-modified iron oxide has been generally loaded in a personal computer. However, along with the increase in the amount of data by processing image data, the capacity thereof has become insufficient and the increase of the capacity of the floppy disc has been demanded.
In the field of the magnetic tape also, along with the prevalence of the office computer, such as minicomputers, personal computers and work stations, magnetic tapes for recording computer data as external storage (a so-called backup tape) have been eagerly studied in recent years. For putting magnetic tapes for such usage to practical use, the improvement of recording capacity has been strongly demanded conjointly with the miniaturization of a computer and the increase of information processing performance (i.e., the increase of throughput) for achieving high capacity recording and miniaturization.
Magnetic recording media comprising a nonmagnetic support having coated thereon a magnetic layer comprising an iron oxide, a Co-modified iron oxide, CrO2, a ferromagnetic metal powder, or a hexagonal ferrite powder dispersed in a binder have been conventionally widely used. In recent years, a magneto resistance head (an MR head) has come to be used for hard disc apparatus in a system using a flexible recording medium. Since an MR head is high sensitivity and capable of obtaining sufficient reproduction output, when a magnetic substance which is relatively low in saturation magnetization as and fine particle is used, a high C/N ratio can be obtained by the reduction of noise. For instance, an example of the reproduction with an MR head by using a barium ferrite (BaFe) fine powder is disclosed in Japanese Patent (Application) Laid-Open No. 302243/1998.
In a recording system of high recording density (in particular, track recording density), it is necessary to optimize the relationship between recording conditions and the medium, besides an MR head is used at reproduction. In high track recording density, the gap of recording heads is generally made small for reducing the influences such as recording demagnetization and bit shift at recording, by which, however, recording magnetic field narrows and overwriting and thickness loss are traded off. Further, since the width of magnetic flux revolution narrows, the influence of turbulence of magnetization in a magnetization transition region cannot be negligible, which results in the loss of S/N ratio and the degradation of overwriting aptitude.